Three of the big server makers have spelt out the steps they are taking to address the burning issue of rising temperatures in the data centre — but their efforts are failing to satisfy some customers, who are having to find their own solutions.

Speaking on Tuesday at The CTO Mandate — an event for IT directors in London's Renaissance Chancery Lane Hotel — Dell, IBM and Fujitsu Siemens all recommended blade servers as one way to cut power consumption. Fujitsu Siemens now sells water-cooled racks to cope with the problem, but for some even this is not enough.

"If I fill all my racks with blades I am going to have a nuclear reactor," said one frustrated consultant who asked not to be named for this article. He explained that he simply cannot get any more servers into his data centre space, where VMWare has been used to virtualise the servers to the point where they are running at 70 to 80 percent server utilisation. A figure of 40 percent is considered good and many data centre servers typically run at between 10 and 30 percent utilisation.

Although this use of virtualisation means more work can be done with fewer servers, the consultant said that because he is paying for data centre space by the square metre, it hurts him to see wastage.

"It is painful for me to see empty space, but I don't want to use water cooling because it is a single point of failure," said the consultant. "I want to fill the whole damn [rack] to the ceiling without water." The power density of the latest servers currently makes this impossible for him.

Speakers from Dell, IBM and Fujitsu Siemens all espoused the value of thermal analysis and design in the data centre.

"The days of the peanut butter spread approach, where you distribute heat across your data centre is gone," said Michael Harpur, UK blade systems manager for HP. "You can and should have sweet spots of cool air and sour spots of hot air, and remember that data centres are data centres, not people centres. Some areas may be hot as hell but that may not necessarily be a problem."

Richard Flanders, enterprise server business development manager at Fujitsu Siemens, also believes in the consultative approach. "With design you can push it to a point but even with this there will be a limit," he said.

And all eyes are currently on the chip manufacturers to help raise that limit. One side-effect of the shift to blade servers is the increased focus this is placing on the power consumed — and hence the heat generated — by the processors inside. IBM's own figures show that as the overall power consumption of a blade server decreases, the percentage of power consumed by a processor rises from 30 percent for a rack server to 46 percent of the total.

In private, server maker senior executives and engineers are becoming increasingly exasperated at what they see as unacceptably high power consumption by Intel's processors.

Ken Loyd of Intel's server platform group, who was also speaking at the event, stressed that Intel is now addressing the problem. "Intel has a history of worrying about power in the mobile side. Now we are doing that in the server side. We have arrived," he said.

One server technology Intel is developing to help here is Foxton, which will adjust the processor voltage and clock frequency to get more performance for the same power consumption. Another is demand-based switching, which is intended to do the opposite — cutting back power consumption while retaining the same performance. But at IBM and HP, the focus is increasingly on AMD chips, which the server makers regard as having better power efficiencies.

AMD says its PowerNow technology enables a processor running at 60 percent utilisation to consume 33 percent less power than when at full throttle, and one running at 40 percent utilisation to consume 62 percent less power.

The CTO Mandate event was run by the European Technology Forum, which is owned by CNET Networks publisher of ZDNet UK.